Download or read book Numerical Modelling of Shallow Water Flows Over Mobile Beds written by Xin Liu and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This Ph.D. thesis aims to develop numerical models for two-dimensional and three-dimensional shallow water systems over mobile beds. In order to accomplish the goal of this dissertation, the following sub-projects are defined and completed. 1: The first sub-project consists in developing a robust two-dimensional coupled numerical model based on an unstructured mesh, which can simulate rapidly varying flows over an erodible bed involving wet-dry fronts that is a complex yet practically important problem. In this task, the central-upwind scheme is extended to simulation of bed erosion and sediment transport, a modified shallow water system is adopted to improve the model, a wetting and drying scheme is proposed for tracking wet-dry interfaces and stably predict the bed erosion near wet-dry area. The shallow water, sediment transport and bed evolution equations are coupled in the governing system. The proposed model can efficiently track wetting and drying interfaces while preserving stability in simulating the bed erosion near the wet-dry fronts. The additional terms in shallow water equations can improve the accuracy of the simulation when intense sediment-exchange exists; the central-upwind method adopted in the current study shows great accuracy and efficiency compared with other popular solvers; the developed model is robust, efficient and accurate in dealing with various challenging cases. 2: The second sub-project consists in developing a novel numerical scheme for a coupled two-dimensional hyperbolic system consisting of the shallow water equations with friction terms coupled with the equations modeling the sediment transport and bed evolution. The resulting 5*5 hyperbolic system of balance laws is numerically solved using a Godunov-type central-upwind scheme on a triangular grid. A spatially second-order and temporally third-order central-upwind scheme has been derived to discretize the conservative hyperbolic sub-system. However, such schemes need a correct evaluation of local wave speeds to avoid instabilities. To address such an issue, a mathematical result by the Lagrange theorem is used in the proposed scheme. Consequently, a computationally expensive process of finding all of the eigenvalues of the Jacobian matrices is avoided: The upper/lower bounds on the largest/smallest local speeds of propagation are estimated using the Lagrange theorem. In addition, a special discretization of the bed-slope term is proposed to guarantee the well-balanced property of the designed scheme. 3: The third sub-project consists in designing a novel scheme to estimate bed-load fluxes which can produce more accurate results than the previously reported coupled model. Using a pair of local wave speeds different from those used for the flow, a novel wave estimator in conjunction with the central upwind method is proposed and successfully applied to the coupled water-sediment system involving a rapid bed-erosion process. It was demonstrated that, in comparison with the decoupled model, applying the proposed novel scheme to approximate the bed-load fluxes can successfully avoid the numerical oscillations caused by simple and less stable schemes, e.g. simple upwind methods; in comparison with the coupled model using same flux-estimator for both hydrodynamic and morphological systems, the proposed numerical scheme successfully prevents excessive numerical diffusion for prediction of bed evolution. Consequently, the proposed scheme has advantages in terms of accuracy which are shown in several numerical tests. In addition, analytical expressions have been provided for calculating the eigenvalues of the coupled shallow-water-Exner system, which greatly enhances the efficiency of the proposed method. 4: The fourth sub-project consists in developing a three-dimensional numerical model for the simulation of unsteady non-hydrostatic shallow water flows on unstructured grids using the finite volume method. The free surface variations are modeled by a characteristics-based scheme which simulates sub- and super-critical flows. Three-dimensional velocity components are considered in a collocated arrangement with a sigma coordinate system. A special treatment of the pressure term is developed to avoid the water surface oscillations. Convective and diffusive terms are approximated explicitly, and an implicit discretization is used for the pressure term. The unstructured grid in the horizontal direction and the sigma coordinate in the vertical direction facilitate the use of the model in complicated geometries. 5: The fifth sub-project consists in developing a well-balanced three-dimensional shallow water model which is able to simulate shock waves over dry bed. Due to the hydrostatic simplification of the vertical momentum equation, the governing system of equations is not hyperbolic and can not be solved using standard hyperbolic solvers. That is, one can not use a high-order Godunov-type scheme to compute all fluxes through cell-interfaces. This may cause the model to fail in simulations of some unsteady-flows with discontinuities, e.g., dam-break flows and floods. To overcome this difficulty, a novel numerical scheme for the three-dimensional shallow water equations is proposed using a relaxation approach in order to convert the system to a hyperbolic one. Thus, a high-order Godunov-type central-upwind scheme based on the finite volume method can be applied to approximate the numerical fluxes. The proposed model can also preserve the ``lake at rest'' state and positivity of water depth over irregular bottom topographies based on special reconstruction of the corresponding parameters. 6: The sixth sub-project consists in extending the result of the fifth sub-project to development of a three-dimensional numerical model for shallow water flows over mobile beds, which is able to simulate morphological evolutions under shock waves, e.g. dam-break flows. The hydrodynamic model solves the three-dimensional shallow water equations using a finite volume method on prismatic cells in sigma coordinates based on the scheme prposed in sub-project 5. The morphodynamic model solves an Exner equation consisting of bed-load sediment transportation. The performance of the proposed model has been demonstrated by several laboratory experiments of dam-break flows over mobile beds.

Download or read book Numerical Modelling of Hydrodynamics for Water Resources written by Pilar Garcia Navarro and published by CRC Press. This book was released on 2007-09-17 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: Overland flow modelling has been an active field of research for some years, but developments in numerical methods and computational resources have recently accelerated progress, producing models for different geometries and types of flows, such as simulations of canal and river networks. Flow in canals has traditionally been described using

Download or read book Numerical Fluid Dynamics written by Dia Zeidan and published by Springer Nature. This book was released on 2022-05-18 with total page 323 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains select invited chapters on the latest research in numerical fluid dynamics and applications. The book aims at discussing the state-of-the-art developments and improvements in numerical fluid dynamics. All the chapters are presented for approximating and simulating how these methods and computations interact with different topics such as shock waves, non-equilibrium single and two-phase flows, elastic human-airway, and global climate. In addition to the fundamental research involving novel types of mathematical sciences, the book presents theoretical and numerical developments in fluid dynamics. The contributions by well-established global experts in fluid dynamics have brought different features of numerical fluid dynamics in a single book. The book serves as a useful resource for high-impact advances involving computational fluid dynamics, including recent developments in mathematical modelling, numerical methods such as finite volume, finite difference and finite element, symbolic computations, and open numerical programs such as OpenFOAM software. The book addresses interdisciplinary topics in industrial mathematics that lie at the forefront of research into new types of mathematical sciences, including theory and applications. This book will be beneficial to industrial and academic researchers, as well as graduate students, working in the fields of natural and engineering sciences. The book will provide the reader highly successful materials and necessary research in the field of fluid dynamics.

Download or read book Mathematical Model of Multi dimensional Shear Shallow Water Flows written by Kseniya Ivanova and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is devoted to the numerical modelling of multi-dimensional shear shallow water flows. In 1D case, the corresponding equations coincide with the equations describing non--isentropic gas flows with a special equation of state. However, in the multi-D case, the system differs significantly from the gas dynamics model. This is a 2D hyperbolic non-conservative system of equations which is reminiscent of a generic Reynolds averaged model of barotropic turbulent flows. The model has three families of characteristics corresponding to the propagation of surface waves, shear waves and average flow (contact characteristics). First, we show the ability of the one-dimensional conservative shear shallow water model to predict the formation of roll-waves from unstable initial data. The stability of roll waves is also studied.Second, we present in 2D case a new numerical scheme based on a splitting approach for non-conservative systems of equations. Each split subsystem contains only one family of waves (either surface or shear waves) and contact characteristics. The accuracy of such an approach is tested on exact 2D solutions describing the flow where the velocity is linear with respect to the space variables, and on the solutions describing 1D roll waves. Finally, we model a circular hydraulic jump formed in a convergent radial flow of water. Obtained numerical results are qualitatively similar to those observed experimentally: oscillation of the hydraulic jump and its rotation with formation of a singular point. These validations demonstrate the capability of the model and numerical method to solve challenging multi--dimensional problems of shear shallow water flows.

Download or read book Quasi three dimensional Numerical Modelling of Flow and Dispersion in Shallow Water written by X.-Y. Jin and published by . This book was released on 1993 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Methods for Shallow Water Flow written by C.B. Vreugdenhil and published by Springer. This book was released on 2012-12-22 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide variety of problems are associated with the flow of shallow water, such as atmospheric flows, tides, storm surges, river and coastal flows, lake flows, tsunamis. Numerical simulation is an effective tool in solving them and a great variety of numerical methods are available. The first part of the book summarizes the basic physics of shallow-water flow needed to use numerical methods under various conditions. The second part gives an overview of possible numerical methods, together with their stability and accuracy properties as well as with an assessment of their performance under various conditions. This enables the reader to select a method for particular applications. Correct treatment of boundary conditions (often neglected) is emphasized. The major part of the book is about two-dimensional shallow-water equations but a discussion of the 3-D form is included. The book is intended for researchers and users of shallow-water models in oceanographic and meteorological institutes, hydraulic engineering and consulting. It also provides a major source of information for applied and numerical mathematicians.

Download or read book The Numerical Modelling of Some Aspects of Shallow Water Flow written by G. P. Dawson and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Shallow Water Flows Using the Discontinuous Galerkin Method written by Abdul A. Khan and published by CRC Press. This book was released on 2014-03-03 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the discontinuous Galerkin (DG) method and its application to shallow water flows. The emphasis is to show details and modifications required to apply the scheme to real-world flow problems. It allows the readers to understand and develop robust and efficient computer simulation models that can be used to model flow, contaminant transport, and other factors in rivers and coastal environments. The book includes a large set of tests to illustrate the use of the model for a wide range of applications.

Download or read book Estuaries and Coastal Zones in Times of Global Change written by Kim Dan Nguyen and published by Springer Nature. This book was released on 2020-02-28 with total page 843 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of extended papers based on presentations given during the ICEC 2018 conference, held in Caen, France, in August 2018. It explores both the limitations and advantages of current models, and highlights the latest developments concerning new numerical schemes, high-performance computing, multi-physics and multi-scale methods, and better interaction with field or scale model data. Accordingly, it addresses the interests of practitioners, stakeholders, researchers, and engineers active in this field.

Download or read book Numerical Simulation in Physics and Engineering Trends and Applications written by David Greiner and published by Springer Nature. This book was released on 2021-04-01 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book results from the XVIII Spanish-French School 'Jacques Louis Lions' on Numerical Simulation in Physics and Engineering, that took place in Las Palmas de Gran Canaria from 25th to 29th June 2018. These conferences are held biennially since 1984 and sponsored by the Spanish Society of Applied Mathematics (SEMA). They also have the sponsorship of the Société de Mathématiques Appliquées et Industrielles (SMAI) of France since 2008. Each edition is organized around several main courses and talks delivered by renowned French/Spanish scientists. This volume is highly recommended to graduate students in Engineering or Science who want to focus on numerical simulation, either as a research topic or in the field of industrial applications. It can also benefit senior researchers and technicians working in industry who are interested in the use of state-of-the-art numerical techniques. Moreover, the book can be used as a textbook for master courses in Mathematics, Physics, or Engineering.

Download or read book Shallow Flows written by Gerhard H. Jirka and published by Taylor & Francis. This book was released on 2004-09-15 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents the key findings of the International Symposium held in Delft in 2003, which explored the process of shallow flows. Shallow flows are found in lowland rivers, lakes, estuaries, bays, coastal areas and in density-stratified atmospheres, and may be observed in puddles, as in oceans. They impact on the life and work of a wide variety of readers, who are here provided with a clear overview of the subject. Shallow flows are intrinsically turbulent. On one hand, there are strongly three-dimensional, small-scale turbulent motions and on the other hand, large-scale quasi-two-dimensional turbulence. This book explains and examines these differences and their effects with sections on transport processes in shallow flows; shallow jets, wakes and mixing layers; stratified and rotating flows in ocean and atmosphere; river and channel flows; and numerical modelling and turbulence closure techniques. The reader is provided with the pick of current studies and a fresh approach to the subject, with expert examination of a fascinating and crucial phenomenon of our world's water systems.

Download or read book Advances in Hydroinformatics written by Philippe Gourbesville and published by Springer. This book was released on 2018-02-26 with total page 1205 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers a collection of extended papers based on presentations given during the SimHydro 2017 conference, held in Sophia Antipolis, Nice, France on June 14–16, 2017. It focuses on how to choose the right model in applied hydraulics and considers various aspects, including the modeling and simulation of fast hydraulic transients, 3D modeling, uncertainties and multiphase flows. The book explores both limitations and performance of current models and presents the latest developments in new numerical schemes, high-performance computing, multiphysics and multiscale methods, and better interaction with field or scale model data. It gathers the lastest theoretical and innovative developments in the modeling field and presents some of the most advance applications on various water related topics like uncertainties, flood simulation and complex hydraulic applications. Given its breadth of coverage, it addresses the needs and interests of practitioners, stakeholders, researchers and engineers alike.

Download or read book Numerical Modelling of Two dimensional Shallow water Flows written by Sami A. Al-Sanea and published by . This book was released on 1981 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling for Coastal Hydraulics and Engineering written by K. W. Chau and published by CRC Press. This book was released on 2014-04-21 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanistic models are often employed to simulate processes in coastal environments. However, these predictive tools are highly specialized, involve certain assumptions and limitations, and can be manipulated only by experienced engineers who have a thorough understanding of the underlying principles. This results in significant constraints on thei

Download or read book Mathematical and Numerical Modelling of Shallow Water Flow written by and published by . This book was released on 1992 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dam Engineering written by Zhongzhi Fu and published by BoD – Books on Demand. This book was released on 2021-03-31 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dams are critical structures in the sense that damage or breach of even a small dam may cause an unacceptable loss of life and property. Therefore, the safety of dams over the intended lifespan is of utmost importance for unrestricted operation. The basic prerequisites for any safe and successful operation of a dam include state-of-the-art design, experimental investigations of the construction material and properties of the foundation, a refined theoretical analysis of relevant load cases, and high-quality construction. In the past decades, many advancements have been achieved in both construction technologies and design, including those for the prediction of the long-term behavior of dams under various loading conditions. As such, this book examines these advancements with respect to the design, construction, and performance of earth, rockfill, and concrete dams. Over eight chapters, this book provides a comprehensive overview of the latest progress and research in dam engineering.

Download or read book Numerical modelling of 2 dimensional shallow water flows written by S. A. A. Al-Sanea and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: